VoIP and Networking Fundamentals: Key Concepts

VoIP and Networking Core Concepts

1. What is an IP-Based PBX?

What is the PBX where all switching is done in IP?

1. IP Enabled PBX
2. Hybrid PBX
3. IP-PBX
4. TDM-PBX

2. Firewalls for IPv6 VoIP Connections

What kind of firewalls are designed to manage VoIP connections in IPv6?

1. Traditional firewalls
2. SIP Application Level Gateways
3. Session Border Controller
4. Jitter Buffer

3. VoIP vs. PSTN: Disadvantages

What is NOT a VoIP advantage over PSTN telephony?

1. Access from anywhere, not constrained to a physical location
2. Security, Resiliency, and Availability
3. It depends on electricity
4. Video conferencing possibilities

4. Asterisk Dialplan Variable Types

Which of the following are NOT variables we can use in Asterisk dialplans?

1. Channel variables
2. Environment variables
3. Global variables
4. Local variables

5. VoIP Convergence: Key Industries

What three industries are involved in VoIP convergence?

• Broadcast
• Telephony
• Internet

6. IPv4 Firewall Issues with VoIP

What problem can arise when using a firewall with IPv4 VoIP connections?

Firewalls often block incoming unsolicited connections. For VoIP, the dynamic nature of RTP ports makes it difficult for the firewall to know which ports to open for the return media stream, leading to dropped calls or one-way audio.

7. Hardware Solution for VoIP Firewall Issues

What hardware can solve the VoIP problem described in the previous question?

ALG (Application Layer Gateway)

8. Optimal VoIP Packetization Interval

What is the recommended packetization interval for VoIP?

10 to 50 ms

9. Impact of Excessive Jitter on VoIP

What happens if delay jitter for a packet is too high?

1. The effect is the same as a packet loss
2. It delays the conversation
3. It produces echo
4. It produces packet overload

10. Main VoIP Signaling Protocol

What is the main protocol used for VoIP signaling?

SIP (Session Initiation Protocol)

11. Main Streaming Media Transmission Protocol

What is the main protocol used for streaming media transmission?

RTP (Real-time Transport Protocol)

12. Main Streaming Media Control Protocol

What is the main protocol used for streaming media control?

RTCP (RTP Control Protocol)

13. New Layer in Video Conferencing

What new layer exists in video conferencing that is not present in basic streaming media?

The conference control layer.

14. Networking Technique: Data Distribution

Identify the networking technique in which one computer sends a single copy of the data over the network, and many computers receive that data.

Multicast

15. FTP Port Numbers Explained

For FTP connections, what port numbers are used for control and data?

For FTP connections, port number 21 is used for control, and port number 20 is used for data.